diff options
| author | Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> | 2017-09-13 09:31:33 +0300 |
|---|---|---|
| committer | Felipe Balbi <felipe.balbi@linux.intel.com> | 2017-09-20 14:57:28 +0300 |
| commit | 9ada8c582088d32bd5c071c17213bc6edf37443a (patch) | |
| tree | f08cbd1a2cc3d37581d2bba9f0e8a8670a5369e4 /drivers/usb/gadget/function/f_printer.c | |
| parent | 97e133d54c1ca8948b191e5721a145a76c4db33d (diff) | |
| download | linux-9ada8c582088d32bd5c071c17213bc6edf37443a.tar.xz | |
usb: gadget: function: printer: avoid spinlock recursion
If usb_gadget_giveback_request() is called in usb_ep_queue(),
this printer_write() is possible to cause spinlock recursion. So,
this patch adds spin_unlock() before calls usb_ep_queue() to avoid it.
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Diffstat (limited to 'drivers/usb/gadget/function/f_printer.c')
| -rw-r--r-- | drivers/usb/gadget/function/f_printer.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/usb/gadget/function/f_printer.c b/drivers/usb/gadget/function/f_printer.c index 8df244fc9d80..ea0da35a44e2 100644 --- a/drivers/usb/gadget/function/f_printer.c +++ b/drivers/usb/gadget/function/f_printer.c @@ -555,6 +555,7 @@ printer_write(struct file *fd, const char __user *buf, size_t len, loff_t *ptr) size_t size; /* Amount of data in a TX request. */ size_t bytes_copied = 0; struct usb_request *req; + int value; DBG(dev, "printer_write trying to send %d bytes\n", (int)len); @@ -634,7 +635,11 @@ printer_write(struct file *fd, const char __user *buf, size_t len, loff_t *ptr) return -EAGAIN; } - if (usb_ep_queue(dev->in_ep, req, GFP_ATOMIC)) { + /* here, we unlock, and only unlock, to avoid deadlock. */ + spin_unlock(&dev->lock); + value = usb_ep_queue(dev->in_ep, req, GFP_ATOMIC); + spin_lock(&dev->lock); + if (value) { list_add(&req->list, &dev->tx_reqs); spin_unlock_irqrestore(&dev->lock, flags); mutex_unlock(&dev->lock_printer_io); |